A father is defined as a maleparent of an offspring.[1] The term "paternal" refers to father, parallel to "maternal" for mother.

According to anthropologist Maurice Godelier, the parental role assumed by human males is a critical difference between human society and that of humans' closest biological relatives - chimpanzees and bonobos - who appear to be unaware of their "father" connection.[2][3]

The father-child relationship is the defining factor of the fatherhood role.[4][5] "Fathers who are able to develop into responsible parents are able to engender a number of significant benefits for themselves, their communities, and most importantly, their children."[6] For example, children who experience significant father involvement tend to exhibit higher scores on assessments of cognitive development, enhanced social skills and fewer behavior problems.[7][8][9]

The father is often seen as an authority figure.[10][11][12][13] According to Deleuze, the father authority exercises repression over sexual desire.[14] Like mothers, human fathers may be categorised according to their biological, social or legal relationship with the child.[15] Historically, the biological relationship paternity has been determinative of fatherhood. However, proof of paternity has been intrinsically problematic and so social rules often determined who would be regarded as a father, e.g. the husband of the mother.

This method of the determination of fatherhood has persisted since Roman times in the famous sentence: Mater semper certa; pater est quem nuptiae demonstrant (Mother is always certain; the father is whom the marriage shows). The historical approach has been destabilised with the recent emergence of accurate scientific testing, particularly DNA testing. As a result, the law on fatherhood is undergoing rapid changes. In the United States, the Uniform Parentage Act essentially defines a father as a man who conceives a child through sexual intercourse.[How to reference and link to summary or text]

The most familiar English terms for father include dad, daddy, papa, pop and pa. Other colloquial expressions include my old man.

Where man in couple originally seeking IVF treatment withdraws consent before fertilisation (UK)

Where the apparently male partner in an IVF arrangement turns out to be legally a female (evidenced by birth certificate) at the time of the treatment (UK) (TLR 1st June 2006)

A biological child of a man who, for the special reason above, is not their legal father, has no automatic right to financial support or inheritance. Legal fatherlessness refers to a legal status and not to the issue of whether the father is now dead or alive.